Sports glasses are employed by many athletes in various sports activities. Typically, such sports glasses are of the “wraparound” variety, which provide lenses having a relatively small radius of curvature. Such lenses are called “Base 8” lenses and are frequently tinted or polarized. Sports, such as mountain biking, skiing, and other sports in which rapid motion is a factor, benefit greatly from wraparound sports glasses, which can reduce glare and provide protection from wind and dust. The more popular sports glasses are semi-rimless, which is more aesthetically pleasing and provides better visibility to the user. Semi-rimless sports lenses are typically affixed to a frame along their upper edges but have lower and side edges that are not enclosed by the frame. On conventional framed glasses, the lower portion of the frame blocks a portion of the user's field of view. Additionally, there is better ventilation for the eyes when there is no bottom rim, which would otherwise tend to act like a gasket or seal around the eyes.
The Base 8 curvature enables tinted lenses to extend around to the side of the wearer's eyes to provide greater protection from the elements than is attainable with stock prescription lenses, which are constructed according to a larger radius of curvature (known in the industry as “Base 6”).
Notwithstanding the advantages of wraparound lenses having Base 8 curvature, many athletes would like to be able to incorporate prescription lenses into wraparound sports glasses frames. Such frames are sturdier and better suited to certain types of physical activity than conventional prescription glasses frames. Heretofore however, it has been difficult to incorporate prescription lenses into sports glasses designed for Base 8 curvature lenses because prescription lenses are made from stock Base 6 curvature lens blanks and these will not fit into sports glasses frames made for Base 8 curvature lenses.
Adapter rings have been proposed for conventional rimmed sports glasses, which will permit a prescription lens to be secured to a sports glasses frame. An example is shown in Hernandez (Publication No. US2006/0050227). Hernandez shows an adapter ring, which may be press-fitted into a sports glasses frame. The Hernandez design suffers from the problem that it is a rimmed frame and, additionally, the adapter ring provides another obstruction to the peripheral vision of the wearer and blocks ventilation as discussed above. Furthermore, the Hernandez design more closely resembles goggles, which from an aesthetic point of view, are less visually pleasing to many sports enthusiasts.